Answer:
Early land animals had both lungs AND gills, and their bodies consisted of few hard parts. Meaning they lacked things like an exoskeleton for instance. Animals today have either lungs OR gills and many have protecting hard parts of their bodies.
Explanation:
Carbohydrates are not important as a stimulus in the gastric phase of gastric secretion, whereas distension, peptides, and low acidity are.
Over the past four decades, researchers have identified many types of oncogenes, including growth factor receptors, transcription factors, and intracellular signaling proteins.
<h3>What are oncogenes?</h3>
These are specific genes in an organism that can cause the formation of cancer. These genes are prone to defects that when activate, signal for a cell to become a tumor. The genes listed in the question are some examples of the types of cells that can be oncogenes.
Therefore, we can confirm that over the past four decades, researchers have identified many types of oncogenes, including growth factor receptors, transcription factors, and intracellular signaling proteins.
To learn more about oncogenes visit:
brainly.com/question/7310602?referrer=searchResults
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A microscope to examine the butterfly. and a small pair of tweezers to pick up and put down the butterfly